In the existing technology, the realization of the major functions of a mobile terminal need the radio frequency of an antenna for signal linking and transmission. Therefore, it is necessary to guarantee good quality of antenna performance. At the same time, in current mobile terminals such as cell phones, due to quality requirements, more and more cell phones use metallic battery lids such as those of stainless steel.
Since the edge of a stainless steel battery lid is quite narrow, in ordinary circumstances, it is very difficult to achieve side grounding. But if no side grounding is done, it will have the following impact: since a metallic part with a large area will have a direct and serious impact on the RF performance of the antenna, a direct consequence is that the antenna performance will be unstable, with poor speech quality.
Therefore, the existing technology uses a local 90 degree curve to increase grounding area. As shown in FIG. 1a, FIG. 1b and FIG. 1c, on the edge of the stainless steel battery lid 110, there is a 90 degree curve grounding part 111. But the existing technology also suffers from several defects:
First, the curve grounding part 111 has a relatively small area and is integral to the stainless steel battery lid 110, so it is prone to poor contact and can thus hardly meet the grounding requirements.
Next, the grounding part 111 of the 90 degree curve must at the same time guarantee a smooth side, in order to meet the electric requirements of grounding contact. Thus, the product defect rate is quite high.
Third, the cost of the mold used to perform such curving is rather high, with a complex production process. Also, it is prone to high wear and tear.
Therefore, the existing technology suffers from defects and needs to be improved and developed.